1. Field of the Invention
The present invention relates to a vertical alignment mode liquid crystal display, and more particularly to vertical alignment mode liquid crystal display for preventing a disclination from being generated.
2. Description of the Prior Art
A twisted nematic mode liquid crystal display (LCD) has been widely used as one of the conventional flat panel display techniques, but it has the disadvantage of providing a narrow viewing angle. For this reason, a vertical alignment mode LCD has been proposed.
A vertical alignment mode LCD in the art is so designed that, as shown in FIG. 1, liquid crystal molecules 6 are aligned in a direction normal to a pixel electrode 3 on a lower substrate 1 as well as a counter electrode 9 on an upper substrate 11 through an influence of a vertical alignment layer. Specifically, the longitudinal axes of liquid crystal molecules 6, contained in the liquid crystal layer between two substrates, are arranged in a direction normal or perpendicular to each of the substrates. Therefore, the vertical alignment mode LCD has an advantage in that it can obtain a high contrast in the direction normal to each of the substrates.
However, the conventional vertical alignment mode LCD has problems as following.
As shown in FIG. 1, when the liquid crystal molecules 6 are arranged in a direction parallel to the substrates 1 and 11 under an electric field, a disclination region A is generated in which a transmittance drops down significantly due to the absence of a preferred arrangement oriented in a certain direction. Due to the disclination region A, the conventional vertical alignment mode LCD has a decreased transmittance and the liquid crystal molecules have a slow response speed.
To solve this problem, a multidomain vertical alignment mode LCD has been proposed so as to provide a preferred arrangement in a certain direction as well as a wide viewing angle. Nevertheless, such a disclination is still generated.